I'm pretty sure the M12 H&R stocks were birch while the commercial 5200 stock was walnut. Either way, they feel like holding a 2x4 to me. The H&R M12 is a fine rifle even if I am not fond of the stocks.

There’s something about the density of birch and other hardwoods that makes a gun handle and feel different than walnut. I think it’s the density. On centerfire, walnut also seems to deal better with recoil, which may be a big reason why it became the dominant species for stock making.